Engine control device and method for a hybrid vehicle

Abstract

The invention comprises an engine control device and method for use in a vehicle incorporating an internal combustion engine and a motor that are capable of transmitting motive power to an axle. The device has an engine utilization reduction portion configured to reduce the power supplied by the engine when a requested engine power is above a predefined engine power minimum value when the device is in a hybrid mode thereby increasing power provided by the electric motor. The device also may have a computer readable engine off portion configured to prevent the engine from starting or consuming fuel thereby causing the vehicle to be directionally powered by the electric motor only. The device may also have a warm up portion configured to operate the engine in warmup mode and limit the power supplied by the engine when the engine temperature is below a predefined engine operating temperature thereby reducing emissions during engine warmup.

Description

FIELD OF THE INVENTION[0001]The invention relates to an engine control device and method for a hybrid vehicle having two different drive units that supply driving force to a driving wheel.BACKGROUND OF THE INVENTION[0002]Hybrid vehicles have been proposed in an attempt to improve fuel economy at least partly in view of adverse environmental effects. Several hybrid vehicles are known that utilize a gasoline engine, an electric motor, and a battery to power a traction wheel. Several types of gasoline electric hybrid vehicles are disclosed in U.S. Pat. No. 7,455,134.[0003]One type of gasoline electric hybrid vehicle does not receive electricity from a source external of the vehicle but utilizes a mechanism that allows the gasoline engine to recharge the battery. The battery stores energy for at least partially powering an electric motor and the vehicle controller determines and signals the proportion of power that should be generated by the electric motor and the gasoline engine based ...

AI Technical Summary

Benefits of technology

"The invention is an engine control device and method for vehicles that use both an internal combustion engine and a motor to transmit power. The device can intercept and modify engine control messages to reduce power output and improve fuel efficiency. It can also prevent the engine from starting or consuming fuel when requested power is too high, and limit power output when the engine temperature is too low. The device can operate the engine in warmup mode and limit power output based on the vehicle's driving mode. Overall, the invention helps optimize engine performance and fuel efficiency in hybrid vehicles."

Problems solved by technology

This method limits the vehicle's speed, for example to 34 mph on a Prius.

Any conversion device using the stock mode of the H-ECU is limited to a maximum vehicle speed of 34 mph in all electric mode.

The first method is limited by other operational factors, such as, battery temperature, battery charge current limit, gasoline engine temperature, and accelerator position.

The first method does not provide for a mode of warming up the engine before the engine is used when switching out of electric only mode.

This causes higher controlled emissions from the engine due to cold starts of the gasoline engine.

This second method limits the amount of electricity utilized because in one type of hybrid vehicle if a high state of battery charge is signaled or reported to the H-ECU, the H-ECU will only use up to about 7 kilowatts of electricity to power the motor for a sustained period.

This third method causes the vehicle to generate diagnostic trouble codes.

These trouble codes may require the operator cycle the vehicle off and back on to restart the gasoline engine.

Restarting the vehicle is often not practical, and under some circumstances, not safe.

This method may also require frequent clearing of the diagnostic trouble codes from the vehicle computer system, which may prohibit the vehicle from meeting many clean air regulations.

Moreover, under the third method, the vehicle is limited to 42 mph when the motor is operating within its rated safety speed.

While this test accurately measures emissions produced, it does not necessarily represent real-world conditions where a driver starts the car and accelerates moderately or quickly before the car has a chance to warm up the catalyst.

This real-world example leads to worse emissions over that emitted in the urban dyno drive.

A problem arising when modifying certain hybrid vehicles, such as to allow it to receive power from a source external of the vehicle and to operate only powered only by the electric motor, is that it is possible to start the car in an electric mode only, where the gas engine is not started and not warmed up, and thus the catalyst or catalytic converter is never heated.

When this occurs, the gas engine is run at high power before the catalyst is warmed up leading to increased emissions.

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